The Hidden Dangers of Carbon Monoxide

A growing trend in recent years has been for EMS providers to have portable carbon monoxide (CO) detectors attached to their first-in bags or radio straps. If your agency purchases these devices, personnel must be trained in what it means and what to do when one alerts. This article discusses what CO is (and isn’t), what meters can tell responders, symptoms of CO poisoning, and prehospital treatment for those with suspected exposure.

CO and Its Detection

CO₂ is carbon dioxide, the byproduct of respiration in humans and a substance plants take in during photosynthesis. This is not the gas we are talking about in this article. Carbon monoxide is a colorless, odorless, toxic, flammable gas formed by the incomplete combustion of carbon. CO is produced from sources such as vehicles, gasoline engines, portable generators, gas-powered tools, camp stoves, burning charcoal and wood, gas ranges, heating systems, and poorly vented chimneys. Structural fires are a common source of CO exposure for both victims and firefighters. CO poisoning is the most common poisoning in the United States and many countries around the world.

Gas meters to measure the concentration of gases like CO in the air come in a variety of forms and big-name brands such as Altair (by MSA), Drager, and BW Technologies (by Honeywell). They can be multigas meters that detect O2, carbon monoxide, and hydrogen sulfide, but most common for EMS use is a single gas meter for the detection of CO. Typically these units, which can be attached to bags or radio straps, cost between $270–$400. Regardless of the brand, the unit is designed to notify users of gas presence with blinking lights, a screen display, and loud audible alarms. Many also vibrate. They can be calibrated to alert at 50 or 100 parts per million. Some units do not require maintenance, while others require a periodic “bump” test. A bump test is brief exposure of the monitor to gas in order to verify that the sensors respond and alarms function accordingly.

While it is not mandatory for EMS units to carry CO alarms, it is recommended. According to a 2018 case study completed in Scotland by Drs. Debkumar Chowdhury and Teresa A. Hand, “The early detection and appropriate management of carbon monoxide poisoning is important, as symptoms may be subtle.” The value of portable meters to detect this cannot be overstated. In December 2018, South Shore Health EMS in Massachusetts saved a family just before Christmas when the portable meter on a bag alerted when responding to a routine sick call.

When the Alarm Sounds

So what does it mean when the alarm activates? Various symptoms will appear based upon the exposure in parts per million (ppm):

Parts per million    Symptoms

35                          Headache, dizziness, flushed skin within 5–8 hours of exposure

200                        Nausea, headache, dizziness, cherry-red skin within 1.5–3 hours of exposure

400                        Life-threatening after three hours

800–1,000             LOC and seizures after an hour; death within 2–3 hours

3,200                     Unconsciousness within 30 minutes

6,400 and above   Instantaneous unconsciousness and death within 10–15 minutes

Since CO calls are often incidental, the initial dispatch might be for a “sick” or “flulike symptoms” call. Carbon monoxide poisoning often mimics flu symptoms, such as nasal stuffiness, fatigue, headaches, nausea, and a feeling of lightheadedness. Cardiac patients are more susceptible to CO symptoms, so a cardiac dispatch could be telling as well. Your index of suspicion should be raised if several people develop symptoms of headache, nausea, and fatigue or drowsiness at the same time. Children and pets are often affected before adults.

Early symptoms of exposure to CO include headache, general body weakness, dizziness, and lethargy. Extended exposure may result in blurry vision, nausea, vomiting, shortness of breath, and altered mental status. CO affects several different sites within the body but is most significant in systems and organs with the highest oxygen requirements, such as the brain, lungs, and heart.

It is important to remember you cannot use a pulse oximeter to determine if a patient has been exposed to CO. While it may display what appears to be a normal oxygen saturation in the upper 90% region, in reality the patient may not have enough oxygen bound to their hemoglobin. A pulse oximeter cannot determine if it is oxygen or carbon monoxide that is bound to the hemoglobin. As a result the only true way to measure is with a portable pulse oximetry-CO meter or with arterial blood gas measurement at the hospital.

Treatment

The first priority if either your CO meter alerts or the patient presents with the above symptoms is to promptly evacuate the structure and call for a fire department and utility company response. Know that if you have been exposed too long, you and your crew might be patients as well. Consider calling for additional ambulances, including ALS if you are a BLS unit.

If the patient is conscious, immediately implement oxygen therapy via a nonrebreather mask at 15 lpm. Consider CPAP or BiPAP if the patient meets the criteria in your system.

If the patient is unconscious, place either an oropharyngeal or nasopharyngeal airway. If their airway is compromised, consider intubation or use an LMA. Continue to provide 100% oxygen therapy.

Commence cardiac monitoring, including a 12-lead, as soon as possible. Monitor all vital signs, including pulse, respirations, blood pressure, and lung sounds. Draw a full set of bloods and establish intravenous access. Notify medical control as well as the receiving hospital and commence rapid transport.

According to emergency physician James MacNeal, DO, stridor, especially if the patient came out of a structure fire, is an ominous sign of impending airway loss. If your scope does not allow rapid sequence intubation, then requesting an ALS unit and notifying the receiving facility early are essential. The properties of ketamine, including pain control and dissociation with preservation of blood pressure and spontaneous respirations, make it an ideal induction agent if approved in your system.

There has been much debate about the use of hyperbaric oxygen to treat victims of CO, but a January 2019 study from Denmark that looked at 23,000 patients with CO poisoning showed it didn’t have an effect on survival. A 2018 case study from Turkey agreed. Regardless, follow your local protocol.

Conclusion

Especially in the cold weather, a large number of EMS calls are related to the flu and seasonal viruses. But don’t be a victim of complacency. Having a CO meter on your person or in your first-in bag might help prevent a tragedy or save a life—including yours.

Resources

Bienick D. EMT carbon monoxide monitor saves South Shore family. WCVB, www.wcvb.com/article/emt-carbon-monoxide-monitor-saves-south-shore-family/25564845.

Centers for Disease Control and Prevention. Carbon monoxide poisoning after a disaster, www.cdc.gov/disasters/carbonmonoxide.html.

Chowdhury D, Hand TA. Acute Despnoea with co-incidental finding of carbon monoxide poisoning—a case report with review of current literature. Int J Crit Care Emerg Med, 2018; 4(1).

MacNeal J. Wheezing, stridor ominous signs of impending airway loss in smoke inhalation. FireRescue1, www.firerescue1.com/fire-products/co-testing/articles/363556018-Wheezing-stridor-ominous-signs-of-impending-airway-loss-in-smoke-inhalation/.

Shochat GN. Carbon Monoxide Toxicity Treatment & Management. Medscape, https://emedicine.medscape.com/article/819987-treatment.

Sonmez BM, Iscanli MD, Parlak S, Dogan Y, Ulubay HG, Temel E. Delayed neurologic sequelae of carbon monoxide intoxication. Turkish J Emerg Med, 2018 Dec; 18(4): 167–9.

Barry A. Bachenheimer, EdD, FF/EMT, is a frequent contributor to EMS World. He is a career educator and university professor, as well as a firefighter with the Roseland (N.J.) Fire Department and an EMT with the South Orange (N.J.) Rescue Squad. His is also an Instructor at the National Center for Homeland Security and Preparedness in New York. Reach him at bbachenheimer@southorangerescuesquad.org